要求：给定一个字符串，请你找出其中不含有重复字符的最长子串的长度
1 class Solution {
2 func lengthOfLongestSubstring(_ s: String) -> Int {
3 var left = 0
4 var right = 0
5 var dic : [String : Int] = [:]
6 let characters : [String] = s.map{String($0)}
7 var lenths : [Int] = []
8
9 for (index, value) in characters.enumerated() {
10 if dic.keys.contains(value) && left <= dic[value]! {
11 left = dic[value]! + 1
12 }
13 dic.updateValue(index, forKey: value)
14 right = index
15 lenths.append(right - left + 1)
16 }
17 return lenths.max() ?? 0
18 }
19 }
